In a "bumper year" for English-language poetry, Nobel laureate Derek Walcott, who was embroiled in scandal two years ago, was tonight named winner of the TS Eliot prize for the best new collection of poems published in the UK or Ireland.

He took the prize against competition from an eclectic group of poets, including fellow Nobel laureate Seamus Heaney, Iraq war veteran Brian Turner and Sam Willetts, whose debut collection came after 10 years lost to addiction to and recovery from heroin.

The winning collection, White Egrets, was described by the chair of judges, poet Anne Stevenson, as "moving and technically flawless".

"It took us not very long to decide that this collection was the yardstick by which all the others were to be measured. These are beautiful lines; beautiful poetry," she said.

Walcott was last the subject of newspaper headlines in 2009, when he withdrew from the election for the post of Oxford professor of poetry after dossiers detailing allegations he had sexually harassed former students were sent to academics.

At the time, he said the process had "degenerated into a low and degrading attempt at character assassination". Ruth Padel, who won the election, denied any role in the smear campaign, but resigned after nine days in post after admitting she had alerted journalists to some of the harassment claims.

Both Walcott and Padel had their supporters in the affair, with the literary world divided over which poet had been more unfairly treated; but Stevenson denied that the episode had influenced the judges. "It was not a consideration," she said. "Extra factors were not considered."

She praised Walcott's technical mastery, saying: "It is a complete book from first to last; each poem belongs completely." She added: "He is a very great poet – one of the finest poets writing in English." The collection – described by the Guardian's reviewer, Sarah Crown, as a "superb meditation on death, grief and the passage of time" – sees Walcott in elegiac mood, the egrets of the title become a shifting metaphor – they "stalk through the rain/ as if nothing mortal can affect them" while his friends "are dying"; their stabbing beaks pluck grubs as greedily as the poet's "pen's beak" searches for nouns. According to Stevenson, the collection "sees a return to his Caribbean setting after sojourns in England and America and he is, as it were, blessing the world instead of complaining about it".

Also on the shortlist of 10 were collections by Simon Armitage, Fiona Sampson, Pascale Petit, Annie Freud, John Haynes and Robin Robertson. Stevenson said the judges could have drawn up "two or three" shortlists in a "bumper year" for poetry "of a very high order". The award also received eager public attention, with the Royal Festival Hall in London packed yesterday evening for readings by the shortlisted poets.

Born in St Lucia in 1930, Walcott won the Nobel prize for literature in 1992. His major work is Omeros (1990), an epic poem weaving a Caribbean setting into material from Homer's Iliad and Odyssey.